An electricity contract that is valid until further notice can always terminated by the consumer with two week's notice. A fixed-term contract ends at the end of the fixed term.
Under general contract terms, relocating to a new address entitles the buyer to terminate a fixed-term contract with two weeks’ notice unless individualised terms of the contract set different conditions.
You can see your electricity provider's conditions for termination in the terms of your contract. The Electricity Market Act sets the minimum terms for termination to which no exceptions are allowed.